Fixing device for an active part of an electric traction machine, stator for an electric traction machine, and motor vehicle

Abstract

The invention relates to a fixing device (10) for an active part (12) of an electric traction machine, which fixing device is designed to fix conductors (20) arranged in respective grooves (16) of the active part (12) in the respective grooves (16) and to seal the grooves (16), wherein the fixing device (10) has a hollow cylindrical main body (24), on the outer side of which a plurality of spring elements (26) are arranged, which are designed to fix the conductors (20) in said grooves (16) and to seal the grooves (16) radially on the inside, by applying said spring elements to respective conductors (22) arranged radially furthest inwards in the respective grooves (16).

Description

[0001] Fixing device for an active part of an electric traction machine, stator for an electric traction machine and motor vehicle

[0002] The invention relates to a fixing device for an active part of an electric traction machine, an active part for an electric traction machine and a motor vehicle with an electric traction machine.

[0003] DE 10 2019214293 A1 discloses a slot wedge for closing a slot of an electrical machine. The slot wedge is a closure element for closing the slot, which is designed as a radial receptacle and is configured to accommodate electrical lines in the form of windings.

[0004] Furthermore, EP 3433 920 B1 discloses a fluid-cooled active part for an electrical machine, wherein the active part is essentially cylindrical or hollow-cylindrical in shape. This active part has axially extending grooves and at least one electrical conductor, which is arranged at least partially in the respective groove and which is composed of a plurality of partial conductors.

[0005] The object of the present invention is to create a solution which enables particularly simple and secure fixing of conductors in respectively assigned grooves of an active part. This object is achieved according to the invention by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description and the figures. Features, advantages and possible embodiments which are set out in the description for one of the subject matter of the independent claims are to be regarded at least analogously as features, advantages and possible embodiments of the respective subject matter of the other independent claims as well as of any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the subclaims.

[0006] The invention relates to a fixing device for an active part of an electric traction machine. The electric traction machine can be designed, in particular, to be used in a motor vehicle for driving the motor vehicle. The active part can be, in particular, a stator or a rotor of the electric traction machine, wherein the rotor can rotate about a rotational axis relative to the stator during operation. The fixing device is designed to fix conductors arranged in respective slots of the active part in the respective slots and to seal the slots. In other words, the active part can comprise an active part core, for example made from a laminated core, which has a plurality of slots. These slots can each be open towards a radially centrally arranged cavity radially enclosed by the active part core.Furthermore, the respective grooves can extend with their longitudinal extension in the axial direction of the active part core. In this case, the grooves can be designed to be open towards the cavity over their entire axial length. The active part can further comprise a plurality of conductors which extend in the axial direction through the respective grooves. The conductors can be so-called hairpin conductors, for example. A cooling fluid, in particular coolant, can flow directly around the respective conductors in the grooves. By sealing the respective grooves by means of the fixing device, in particular towards the cavity radially enclosed by the active part core, undesired leakage of the cooling fluid, in particular the coolant, into the cavity of the active part can be prevented.This enables particularly reliable cooling of the conductors by means of the cooling fluid, in particular the cooling liquid. The fixing device is provided with a hollow-cylindrical base body, on the outside of which several spring elements are arranged. The spring elements are designed to fix the conductors in the respective grooves by engaging the respective radially innermost conductors in these grooves and to seal the grooves radially inward.In other words, by applying the respective spring elements to the respective radially innermost conductor in the respective slots, all of the conductors arranged in the respective slots are subjected to a force acting outwards in the radial direction by the spring elements, whereby all of the conductors in the respective slot are pressed towards one another in the radial direction, in particular additionally against a wall of the groove that bounds the groove outwards in the radial direction, whereby the conductors are fixed in the respective slots. By means of the fixing device, all of the conductors in the respective slots of the active part can thus be pressed together in the radial direction and thereby fixed in place by applying the respective spring elements of the fixing device to those conductors in the respective slots that are radially closest to a central axis of the active part.The fixing device thus enables particularly simple fixing of the conductors and additionally sealing of the respective grooves in the radial direction towards the cavity of the active part.

[0007] In a possible development of the invention, it is provided that a shape of the respective spring elements and / or a spring hardness of the respective spring elements is selected depending on a predetermined clamping effect to be achieved for the conductors in the respective grooves. In other words, a respective design of the spring elements can be selected depending on how many conductors are arranged in the respective grooves or what the cross-sectional ratio of the respective conductors arranged in a groove is to the groove. Depending on how many conductors are arranged in the respective grooves or what the cross-sectional ratio is, a clamping effect necessary for fixing the conductors in the respective groove, which clamping effect is to be brought about by the respective spring element assigned to this groove, can be determined.By designing the respective spring elements with regard to their geometry and / or spring hardness, it can be achieved, when the fixing device in the active part is used as intended for fixing the respective conductors in the grooves, that the conductors are reliably fixed in the respective grooves by means of the fixing device and a relative movement of the respective conductors in the grooves to one another is prevented by introducing the clamping effect when the fixing device is used as intended.

[0008] In a further possible embodiment of the invention, it is provided that at least one of the spring elements is designed as a bow spring. A bow spring has the shape of a bow. For example, the bow spring can be produced by bending a wire. A bow is a more or less curved, slender object. A spring element is an elastically deformable element. By building up a spring force in the respective spring elements, the spring elements fix the conductors in the respective grooves by pressing the conductors together. Configuring the respective spring elements as bow springs enables a particularly simple and robust design of the spring elements.

[0009] In a further possible embodiment of the invention, it is provided that at least one of the spring elements is made of a metallic material and / or the base body is made of a plastic. The spring elements made of the metallic material are particularly stable and thus consequently designed to particularly reliably clamp respective conductors arranged together in a groove and thereby fix them in the respective groove. The design of the base body from the plastic enables a particularly lightweight design of the base body. Furthermore, due to the design of the base body from the plastic, the respective spring elements can be electrically insulated relative to one another, whereby a current flow from one spring element to another spring element and consequently a short circuit of the active part via the fixing device can be particularly effectively avoided.

[0010] In this context, it can be provided, in particular, that the at least one spring element made of the metallic material is coated or overmolded with plastic. In this case, the at least one spring element can, in particular, be encased in the plastic and can thereby be designed to be particularly reliably electrically insulated from the outside. As a result, the risk of a short circuit occurring in the active part via the fixing device is particularly low. Coating the respective spring elements with the plastic makes it possible to achieve a particularly uniform layer thickness of plastic over the entire surface of the respective spring elements. As a result, the respective spring elements can be electrically insulated from the outside with particularly little plastic material consumption.The overmolding of at least one spring element with the plastic enables a particularly reliable complete enveloping of the spring element with the plastic, whereby the spring element can be particularly reliably electrically insulated from the outside.

[0011] In an alternative possible embodiment of the invention, it can be provided that at least one of the spring elements is made of a plastic and / or the base body is made of the plastic. In this case, the at least one spring element and the base body can be made of the same plastic or of different plastics. The design of the at least one spring element from the plastic enables this spring element to be particularly lightweight and, moreover, electrically insulating. The risk of the spring element triggering a short circuit in the active part is therefore particularly low. The design of the base body from the plastic enables particularly simple production of the base body and a particularly lightweight design of the base body.

[0012] The invention further relates to an active part for an electric traction machine, comprising a hollow-cylindrical active part core having a plurality of grooves. These grooves are each open toward a radially centrally arranged cavity radially enclosed by the active part core, and extend with their longitudinal extension in the axial direction of the active part core. The active part core can be formed, for example, from a laminated core. The active part further comprises a plurality of conductors which extend in the axial direction through the respective grooves. Furthermore, the active part comprises a fixing device as already described in connection with the fixing device according to the invention. This fixing device is arranged in the cavity of the active part core and rests with its outer side against an inner side of the active part core which closes off the cavity radially inward.As a result, the respective spring elements of the fixing device are each applied to a radially innermost conductor of the grooves assigned to the respective spring elements, whereby all conductors in a respective groove are pressed together in the radial direction. The spring elements enable the respective conductors, to which the spring elements are applied, to be subjected to a spring force in the radial direction from the inside to the outside and thus radially outwards away from the cavity, whereby all conductors in a respective groove are pressed towards one another in the radial direction. Because all spring elements are held on the base body of the fixing device, the fixing device enables simultaneous positioning of all spring elements relative to the active part. As a result, the spring elements can be applied to the respectively assigned conductors particularly easily.This eliminates the need for complex, individual positioning of the respective spring elements. Furthermore, the base body can cover, in particular seal, all grooves of the active core in the radial direction toward the cavity. This effectively prevents the radial outflow of a cooling fluid, in particular a coolant, from the grooves. The fixing device can thus form a closure of the respective grooves radially inward and thus toward the cavity, and furthermore, enable the fixing of the respective conductors in the grooves of the active core.

[0013] In this context, it can be provided, in particular, that the fixing device has at least one spring element for each groove, in particular at least two spring elements for each groove, which are arranged one behind the other in the axial direction. This means that, by means of the fixing device, all conductors in all grooves of the active part core are fixed by means of the fixing device because at least one spring element is provided for each groove. For each groove of the active part core, at least one spring element is thus applied to the conductors arranged radially furthest inside, whereby all conductors in each groove are fixed by means of the fixing device by means of a radial compression of the respective conductors in each of the grooves.If the fixing device comprises a plurality of spring elements which are arranged one behind the other in the axial direction on the outside of the base body and are assigned to the same groove, then the conductor arranged furthest radially inside in this groove and thus closest to the cavity can be subjected to a spring force at a plurality of points along its axial longitudinal extent. As a result, this conductor can be pressed radially outwards particularly evenly over its entire axial length and thus towards the other conductors arranged in this groove. This makes it possible to achieve a particularly even fixing of all conductors in a respective groove over their entire axial length.

[0014] In a further possible embodiment of the invention, it is provided that the base body of the fixing device rests without play against the inner side of the active part core, which closes off the cavity radially inwards. By placing the base body of the fixing device against the inner side of the active part core without play, it can be achieved that the base body rests against the entire inner side of the active part core over a large area without a gap extending in the radial direction between the inner side of the active part core and the base body. This can ensure that the respective grooves of the active part core are reliably sealed radially inwards towards the cavity by means of the fixing device, in particular by means of the base body.

[0015] The invention further relates to a motor vehicle with an electric traction machine, which comprises at least one active part, as already described in connection with the active part according to the invention. The electric traction machine is particularly configured to drive the motor vehicle using electrical energy, in particular using electrical energy provided by a traction battery of the motor vehicle. The motor vehicle is, in particular, a motor vehicle, in particular a passenger car.

[0016] Further features of the invention may emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0017] The drawing shows:

[0018] Fig. 1 is a schematic perspective view of a fixing device for a

[0019] Active part of an electric traction machine; and Fig. 2 shows a schematic sectional view of a section of an active part with the fixing device.

[0020] In the figures, identical and functionally identical elements are provided with the same reference numerals.

[0021] Fig. 1 shows a schematic perspective view of a fixing device 10 for an active part, in this case a stator 12, of an electric traction machine. The stator 12 is shown in detail in Fig. 2 in a schematic sectional view. The stator 12 can be part of an electric traction machine which is designed to drive a motor vehicle using electrical energy. For this purpose, the electric traction machine can comprise, in addition to the stator 12, a rotor which, during operation, can be rotated relative to the stator 12 about an axis of rotation. The stator 12 comprises an active part core designed as a stator core 14, which in this case is formed from a laminated core. This stator core 14 has a plurality of slots 16 which extend over an entire length running in the axial direction A of the stator 12, which length runs into the image plane in Fig. 2.The stator core 14 is in the present case designed as a hollow cylinder, which means that the stator core 14 encloses a hollow space 18 radially outwards.

[0022] The respective grooves 16 are designed to be open towards the cavity 18 and thus radially inward, as can be seen particularly clearly in Fig. 2. In each of the grooves 16, a plurality of conductors 20 are arranged one behind the other in the radial direction R. For reasons of clarity, only individual ones of the conductors 20 are provided with the corresponding reference numeral. Because the respective conductors 20 are arranged one behind the other in the radial direction R in the respective grooves 16, there is a radially innermost conductor 20 in each groove 16, which in the radial direction R with respect to the cavity 18 is arranged closest to the cavity 18 in the respective groove 16 and which is designated below by the reference numeral 22.In order to fix the respective conductors 20 in the respectively assigned groove 16, it is provided that the respective radially innermost conductor 20 is pressed radially outwards in each of the grooves 16, whereby all conductors 20 within a groove 16 are clamped together and thereby fixed relative to one another and with regard to their position within the groove 16. The radially innermost conductors 22 are subjected to the force acting in the radial direction R by means of the fixing device 10. The fixing device 10 comprises a hollow cylindrical base body 24, which in this case is made of a plastic. In addition, the fixing device 10 comprises a plurality of spring elements 26, which are arranged radially on the outside of the base body 24. For reasons of clarity, only individual spring elements 26 are provided with the corresponding reference numerals in Fig. 1.The spring elements 26, like the base body 24, can also be made of a plastic, whereby the spring elements 26 and the base body 24 can be made of the same plastic or of different plastics. Alternatively, the spring elements 26 can be made of a metallic material, in particular in the form of bow springs. If the fixing device 10 comprises the spring elements 26 made of the metallic material, these spring elements 26 can be coated or overmolded with an electrically insulating plastic for electrical insulation. As can be seen in Fig. 2, the fixing device 10 has at least one spring element 26 for each groove 16.For fixing the respective conductors 20 in the respectively associated groove 16, the fixing device 10 is arranged in the hollow space 18 and at least one spring element 26 is applied radially from the inside to each radially innermost conductor 22, whereby the radially innermost conductor 22 is pressed radially outwards by means of the respective spring element 26 and thereby the conductors 20 arranged within a groove 16 are clamped together.

[0023] The axial direction A of the stator 12 coincides with the axial direction A of the fixing device 10. The axial direction A runs parallel to a central axis of the stator 12 and to a central axis of the base body 24. The radial direction R is perpendicular to the axial direction A.

[0024] In order to enable uniform clamping of the respective conductors 20 within a groove 16 over their entire length running in the axial direction A, the fixing device 10 can have a plurality of spring elements 26 per groove 16, wherein these plurality of spring elements 26, which are assigned to the same groove 16, are arranged one behind the other in the axial direction A on the base body 24, as can be seen particularly clearly in Fig. 1. It can be provided that a shape of the respective spring elements 26 and / or a spring hardness of the respective spring elements 26 is selected depending on a predetermined clamping effect to be achieved of the conductors 20 in the respective grooves 16. As can also be seen in Fig. 2, it is provided that the base body 24 of the fixing device 10 rests without play against the inner side 28 of the stator core 14, which radially inwardly closes off the cavity 18.As a result, the respective slots 16 are sealed radially inward by means of the base body 24. The fixing device 10 is thus a combination component for sealing the respective slots 16 and for securing the conductors 20 in the respective slots 16. In the present case, the base body 24 is tubular in shape, so that when the base body 24 is arranged in the cavity 18, all slots 16 and the entire inner side 28 of the stator core 14 are covered radially inward by the base body 24.

[0025] By inserting the tubular base body 24 into the cavity 18, a sealing effect can be achieved for coolant-carrying channels near the conductors in the respective slots 16, in particular toward a rotor chamber. This rotor chamber is arranged in particular in the cavity 18. In other words, when the stator 12 is used as intended in the electric traction machine, a rotor is arranged in the cavity 18 and is thus covered radially outward by the stator 12 at least in an axial length region. By using spring-like bodies, in this case the spring elements 26, a clamping effect of the conductors 20 in the respective slots 16 can be achieved. The combination of the spring elements 26 with the tubular base body 24 enables both the sealing effect and the conductor clamping by means of the fixing device 10.Because all spring elements 26 are held on the base body 24, the spring elements 26 can be handled particularly easily, since only the fixing device 10 needs to be installed as a separate component in order to achieve the effects described above. The spring action of the spring elements 26 allows simple tolerance compensation of the stator core 14 and the conductors 20. By varying a spring shape of the respective spring elements 26, whereby a spring constant of the respective spring elements 26 can be adjusted, the respective spring force acting outwards in the radial direction R and introduced into the respective slots 16 can in turn be adjusted. In this way, the clamping effect of the conductors 20 can be adjusted by varying the spring shape of the respective spring elements 26.Due to the conductor clamping or fixing of the conductors 20 by means of the fixing device 10, resin dripping for fixing the conductors 20 in the respective grooves 16 can be dispensed with, thereby preventing unwanted filling of cooling channel geometries in the area of ​​the conductors 20. Overall, the invention shows how a component for fixing the conductors, in this case the fixing device 10, can be created for the stator 12 of the electric traction machine.

[0026] List of reference symbols

[0027] 10 Fixing device 12 Stator

[0028] 14 Stator core

[0029] 16 grooves

[0030] 18 cavity

[0031] 20 conductors 22 radial innermost conductor

[0032] 24 basic bodies

[0033] 26 spring element

[0034] 28 Inside

[0035] A axial direction R radial direction

Claims

Patent claims 1. Fixing device (10) for an active part (12) of an electric traction machine, which is designed to fix conductors (20) arranged in respective slots (16) of the active part (12) in the respective slots (16) and to seal the slots (16), wherein the fixing device (10) has a hollow cylindrical base body (24), on the outside of which a plurality of spring elements (26) are arranged, which are designed to fix the conductors (20) in these slots (16) by applying them to respective radially innermost conductors (22) in the respective slots (16) and to seal the slots (16) radially inwards.

2. Fixing device (10) according to claim 1, characterized in that a shape of the respective spring elements (26) and / or a spring hardness of the respective spring elements (26) is selected depending on a predetermined clamping effect to be achieved of the conductors (20) in the respective grooves (16).

3. Fixing device (10) according to claim 1 or 2, characterized in that at least one of the spring elements (26) is designed as a bow spring.

4. Fixing device (10) according to one of the preceding claims, characterized in that at least one of the spring elements (26) is made of a metallic material and / or the base body (24) is made of a plastic.

5. Fixing device (10) according to claim 4, characterized in that the at least one spring element (26) made of the metallic material is coated or overmolded with plastic.

6. Fixing device (10) according to one of claims 1 to 3, characterized in that at least one of the spring elements (26) is made of a plastic and / or the base body (24) is made of a plastic.

7. Active part (12) for an electric traction machine, with a hollow cylindrical active part core (14) which has a plurality of grooves (16), each of which is open towards a radially centrally arranged cavity (18) radially enclosed by the active part core (14) and extends with their longitudinal direction in the axial direction (A) of the active part core (14), with a plurality of conductors (20) which extend in the axial direction (A) through the respective grooves (16), and with the fixing device (10) according to one of the preceding claims, which is arranged in the cavity (18) and with its outer side abuts an inner side (28) of the active part core (14) which radially closes off the cavity (18) inwards, whereby the respective spring elements (26) of the fixing device (10) each engage a radially innermost conductor (22) of the grooves (16) assigned to the respective spring elements (26). are created,whereby all conductors (20) are pressed against each other in a respective groove (16) in the radial direction (R).

8. Active part according to claim 7, characterized in that the fixing device (10) has at least one spring element (26) for each groove (16), in particular at least two spring elements (26) for each groove (16), which are arranged one behind the other in the axial direction (A).

9. Active part according to claim 7 or 8, characterized in that the base body (24) of the fixing device (10) rests without play on the inner side (28) of the active part core (14) which closes off the cavity (18) radially inwards.

10. Motor vehicle with an electric traction machine which comprises at least one active part (12) according to one of claims 7 to 9.

Images